Conventional vegetable pastas, such as spinach- and tomato-containing pastas, consist mainly of wheat flour with only about 3 to 3.5 weight percent or less vegetable solids. Attempts to prepare wheat flour-based vegetable pastas with higher vegetable solids levels have generally been unsatisfactory.
Processes for the commercial manufacture of pasta, including vegetable pasta with low levels of vegetable solids, are well known. These processes involve mixing flour and water and, in the case of vegetable pasta, the appropriate vegetable solids, to form a paste. Typically the paste is shaped by forcing it through holes in an extruder die at high pressure and elevated temperature to form extrudates of the desired cross-sectional shape. The extrudates may, if desired, be cut to desired lengths. The extrudates are usually dried to a moisture content of generally less than about 14 weight percent.
The drying process in a conventional pasta manufacturing process is lengthy. The extrudates as they leave the extruder generally have a moisture content of about 28 weight percent or higher. For shelf-stable pasta, the moisture content of the pasta must generally be reduced to below about 14 weight percent. To accomplish this, conventional long and short pasta goods are generally dried to a moisture content of about 10 to 13 weight percent under normal drying conditions using temperature in the range of about 40.degree. to about 60.degree. C. with maximum drying times of about 10 hours for short pasta goods (i.e., elbow macaroni, elbow spaghetti, shells, mafalda, and the like) and about 20 hours for long pasta goods (i.e., spaghetti, fettuccine, vermicelli, and the like). Under high temperature drying conditions in the range of about 60.degree. to about 80.degree. C., short pasta goods are dried for a maximum of about 5 hours and long pasta goods are dried for a maximum of about 10 hours. For ultra high temperature drying conditions in the range of about 80.degree. to about 140.degree. C., short pasta goods are dried for a maximum of about 2 hours and long pasta goods are dried for a maximum of 5 hours. In most cases, the only process parameters controlled are the temperature, the relative humidity of the drying air and the drying time. In order to avoid checks, cracks, and like defects in the pasta, the conventional drying process is a relatively slow and time consuming, often requiring up to about 36 hours for long goods or 12 hours for short goods, for the pasta to reach the desired moisture content of less than 14 weight percent. During much of the drying process, the pasta is subjected to elevated temperatures which, if vegetable solids are present, adversely affect the color, flavor, texture and nutritional value of the finished pasta product.
Incorporation of flavoring and/or coloring agents, such as spinach or tomato solids, at levels up to about 3 weight percent can sometimes result in a pasta product with a starchy or gummy texture. Moreover, such vegetable pastas generally do not retain their color upon shelf aging or when cooked for eating. Better color can be obtained by increasing the level of vegetable solids in the pasta accompanied by properly controlled processing conditions. Attempts to increase the vegetable solids content above about 3.5 weight percent in dried, shelf-stable pasta have, however, generally resulted in products which lack integrity and with a tendency to fall apart during or after cooking. Such pasta also does not have desirable texture properties and generally, the overall quality is unacceptable. Thus, commercially available dried vegetable pasta generally has about 3 to 3.5 weight percent or less vegetable solids, and tends to change in color and flavor during processing, storage and upon cooking.
Some attempts have been made to preserve or enhance the color in dried vegetable pasta. For example, U.S. Pat. No. 4,840,808 discloses preparing vegetable pasta containing about 3 weight percent chlorophyll-containing vegetable solids and cations selected from the group consisting of magnesium, zinc, copper, calcium, and aluminum in order to enhance and preserve the color. The vegetable powders are subjected to an alkaline treatment prior to addition to the pasta dough in order to hydrolyze the chlorophyll ester groups and stabilize the chlorophyll pigment. U.S. Pat. No. 4,517,215 discloses the use of hydrocolloids such as sodium or potassium alginate, at about 0.25 to 3 weight percent, and propylene glycol alginates, also at about 0.25 to 3 weight percent, to prepare vegetable pastas where the main ingredient is a seed or tuberous vegetable such as corn, potato, beans, and peas. Such vegetable pastas do not contain significant amounts of wheat-type flour. European Patent Publication 0,518,097A1 discloses that the color stability of vegetable pasta can be enhanced by subjecting the fresh pasta to saturated steam at 70.degree. to 80.degree. C. followed by drying at temperatures below 60.degree. C. and a relative humidity of about 75 percent to a final moisture content of about 11 percent.
As indicated, the amount of vegetable solids in conventional dried wheat-based pasta has generally been limited to about 3 to 3.5 weight percent or less. Such vegetable pastas tend to loose color and flavor during the drying process, upon storage, and especially upon cooking. For example, green or chlorophyll-containing vegetable pastas, e.g., spinach pastas tend to turn brown; and the reddish color in tomato pasta tends to fade over time. Moreover, even if the color remains strong in the dried pasta, there is generally a substantial loss of color upon cooking. A general reduction in both flavor and nutritional values is also observed with conventional vegetable pastas upon storage. The inability to incorporate higher levels of vegetable solids into dried pasta and to maintain color and flavor, has also generally limited the types of vegetables that could be utilized to those with very intense coloration or pigmentation such as spinach or tomato. In general, flavor retention has not been a primary concern in commercial vegetable pasta products.
More recently, U.S. Pat. No. 5,124,168 (June 23, 1992) provides a vegetable pasta having up to about 10 weight percent vegetable or herb solids which reportably retained enhanced flavor, color, and texture and, when dried, had a shelf life longer "than flavored pasta products currently in the market." The basic pasta product contained between about 40 to 80 percent pasta flour, about 1 to 10 percent egg (e.g., whole egg, egg white from whole egg, or dehydrated egg white), about 0.2 to 5 percent starch complexing agent, olive oil in an amount sufficient to facilitate the extrusion of the pasta product and to bind the non-pasta flour ingredients to the pasta flour (i.e., about 1 to 5 percent), and sufficient water for blending. The pasta could contain up to about 10 percent of a "flavor component" selected from the group consisting of tomato, parsley, calamari, lemon, garlic, curry, carrot, porcini, mushroom, black pepper, dill, cilantro, serrano, green pepper, red pepper, tarragon, and combinations thereof. The pasta could be used fresh or it could be dried under relatively low temperature and relatively high humidity conditions. The maximum drying temperature was between about 58.degree. and 70.degree. C. in order "to protect the organoleptic properties of the formulations." The reported relative humidity during drying was in the range of about 85 to 92 percent. The drying process consisted of four distinct stages: (1) an initial pre-drying stage having a preferred temperature of about 30.degree. C. and a preferred relative humidity of about 85 percent; (2) a pre-drying stage having a preferred temperature of about 30.degree. C. and a preferred relative humidity of about 85 percent; (3) a drying stage having several substages over a 14 to 15 hour period; and (4) a post-drying stage where the pasta is equilibrated with ambient temperature and humidity conditions. The drying stage included three separate substages: (1) a "case hardening" substage wherein the pasta product is subjected to a draft of air to set the exterior shape; (2) a high humidity substage where the humidity is raised to about 92 percent and where the temperature is raised to about 70.degree. C., then lowered to about 55.degree. C. and held at that temperature for about 2 hours; and (3) a final substage wherein the temperature is lowered to about 30.degree. C. over about a twelve hour period during which time the humidity is also lowered "in proportion to the drop in temperature." The drying process should bring the moisture content of the pasta down from about 30 percent to about 12 percent in about 14 to 15 hours.
The inability to provide vegetable pastas and herb pastas with good texture, flavor, color and nutritional value as well as good storage stability has limited the use of such pastas. Fresh vegetable and herb pastas generally exhibit very limited shelf lives because of their tendency to undergo chemical changes, including flavor and color degradation.
It would be desirable, therefore, to provide a method by which dried vegetable or herb pasta could be prepared with higher levels of vegetable or herb solids than is currently commercially available. It would also be desirable to provide dried vegetable or herb pastas with high levels of vegetable or herb solids, respectively, which have good color, texture, structural integrity, and vegetable or herb flavors. It would also be desirable to provide dried vegetable or herb pastas with high levels of vegetable or herb solids, respectively, which retain their color, texture, integrity, and vegetable or herb flavor upon cooking. It would also be desirable to provide dried vegetable or herb pastas with high levels of vegetable or herb solids, respectively, which are more visually appealing, i.e., more colorful, in both the dried and cooked state and which are more flavorful and nutritious than conventional vegetable or herb pastas. It would also be desirable to provide dried vegetable or herb pastas with enhanced color and color stability without the need to add color stabilizers, enhancers, artificial coloring, or other stabilizing ingredients to the product. It would also be desirable to provide dried vegetable or herb pastas with improved storage stability. It would also be desirable to provide such just-described vegetable or herb pastas without the need to add egg-containing ingredients and/or oil. It would also be desirable to provide essentially egg-free and/or oil-free vegetable or herb pastas having high levels of vegetable or herb solids, respectively. The present invention provides such processes and such dried vegetable and herb pastas.